Composite video signals, commonly used in video broadcasts or transmissions, contain a brightness signal (luminance, luma or Y) and a color signal (chrominance, chroma or C), where the color signal is modulated into a color sub-carrier and added to the brightness signal prior to transmission. To effectuate demodulation of the color sub-carrier upon reception, receivers for color displays include a Y/C separator to separate luminance and chrominance components from the composite video signal. Y/C separators, however, often permit crosstalk, e.g., when luma is separated into the chrominance component (cross chroma) and chroma is separated into the luminance component (cross luma). The Y/C crosstalk generally degrades the quality of displayed video pictures.
One technique to reduce Y/C crosstalk is to separate composite video signals according to their temporal changes using three-dimensional (3D) comb filters. Previous 3D comb filtering, however, has been confined to Y/C separation, which limits its use to composite video signals and complicates the development of a multi-standard 3D comb filter. Furthermore, applying the 3D comb filters before the demodulation of the color sub-carrier requires special circuitry to detect locking of the horizontal and chrominance frequencies. Accordingly, a need remains for a system and method for improved temporal processing of video signals.